THIS SUBPROPOSAL CONSTITUTES A PILOT PROJECT EXAMINING THE EVENTS UNDERLYING GROSS TISSUE DEGENERATION. THE MODEL SYSTEM IS HOLOTHUROIDEAN ISOSTICHOPUS BADIONOTUS. THIS ANIMAL EXHIBITS EXTREME PRESSURE DEPENDENT LOCAL DEGENERATION OF THE BODY WALL. A MAJOR COMPONENT OF THE BODY WALL IS A THICK CONNECTIVE TISSUE LAYER. THE MECHANISM IS UNCLEAR BUT MAY INVOLVE CALCIUM DEPENDENT CELL DEATH AND ENZYME ACTIVATION. INITIAL STUDIES SHOW A MARKED AND TRANSIENT INFLUX OF CALCIUM DURING THE FIRST STAGES OF DEGENERATION SUGGESTING THE POSSIBILITY OF CALCIUM MEDIATED EVENTS. THESE EVENTS, BOTH FLUX AND DEGENERATION, ARE OBVIATED BY THE ADDITION OF ANTIOXIDANTS SUGGESTING A ROLE OF FREE RADICALS.